Dried spices and herbs, most often in their ground form, are used in the preparation of foods and beverages to add flavor, aroma, color, and preservative properties that make the food or beverage more palatable and appealing. The dried spices, ground or unground, are usually added to the food or beverage during the preparation at such a point in the preparation that time is allowed for the principal components of interest to be extracted into the food or beverage to impart the desired combination of attributes to the food or beverage. Further, as spices and herbs are notoriously known to have inconsistent levels of the flavor, aroma, color, or antioxidants, it is commonly required that spices of varying levels of the principal components of interest be blended to make a final product that is consistent with regard to the principal components of interest to achieve predictable and repeatable performance with respect to the flavor, aroma, color, or antioxidant release into the food or beverage system in which they are used. This is a costly and time consuming process.
As suggested in prior art, much of the flavor, aroma, and/or color often is not effectively transferred to the food or beverage. U.S. Pat. No. 2,507,084 overcomes this obstacle of under-utilization of the principal components of interest by first extracting the principal components of interest and subsequently coating the spent spice from the extraction process with a portion of the extract originally removed, thereby extending the useful amount of flavor and aroma that can be derived from a given quantity of spice. It is also disclosed that this process derives value from the exhausted spice solids, from which the flavor, aroma, color, or antioxidants have been removed, which would otherwise be a waste product. This is a complicated and costly process for recovery of the maximum value of the principal components of interest.
Traditional methods for the sterilization of ground spices and extracts involve the use of extremely toxic substances such as ethylene oxide or methyl bromide, non-edible solvents which are inherently difficult to remove from the plant solids, irradiation, or steam and moisture treatment to reduce plate counts to acceptable levels for use in foods and beverages. Chemical sterilization, irradiation, and non-edible solvent extraction of spices are disagreeable to the consumer because of the perceived risks of residual chemicals and/or radiation remaining in the plant matter and, as a result, several processes using added moisture, such as water or steam, at elevated pressures have been developed as alternatives. Typical sterilization procedures are disclosed in U.S. Pat. Nos. 4,210,678, 4,790,995, and 4,910,027. All sterilization processes are inherently costly in that they require a separate processing step or steps to accomplish the sterilization, and also present the possibility of further degrading the more unstable components. Addition of moisture or water vapor, as disclosed in U.S. Pat. Nos. 4,210,678 and 4,910,027, prior to or during the heating and sterilization process, results in a cooked aroma not typical of the fresh, dehydrated spice and also results in steam distillation and loss of some of the volatile flavor and aroma constituents.
Traditional extraction processes for the manufacture of concentrated extracts (concentrated several fold as compared with the raw material) involve not only the use of various non-edible solvent systems, but also a large proportion of solvent in relation to the compounds of interest. Many require the use of petroleum distillates, chlorinated solvents, or highly flammable solvents which must be eliminated almost completely from the finished products to make them safe for consumption. These systems require expensive distillation equipment and special precautions must be taken to ensure worker safety and to limit environmental impact. The intensive processing required often destroys, modifies, or loses some of the more unstable compounds, delicate aromas, flavors, or pigments. More significantly, the last traces of undesirable non-edible solvents are very difficult to separate from the concentrated extract. The residual solid must necessarily contain the same residual non-edible solvents, which are removed only with difficulty. Such residual solvents limit the potential use of the residual solid for human consumption, and are potential environmental contaminants.
Other concentration techniques rely on high pressure equipment to obtain good solvating properties from gases, e.g., liquid or supercritical CO.sub.2 (U.S. Pat. No. 4,490,398). High pressure liquefied or supercritical gas extraction requires expensive equipment and has limited solvating abilities for some compounds requiring the addition of co-solvents, or solvents such as propane and butane, which are also difficult to control and may be environmentally sensitive or undesirable in a finished product.
Following extraction and desolventization, the concentrated extract is often standardized with edible solvents and emulsifiers to provide a concentrate with reproducible levels of the active or principal compounds of interest to the user.
In an effort to overcome the shortcomings and risks associated with the above-mentioned processes, extraction has been carried out using edible solvents such as vegetable oils or lard. Typical extraction procedures are disclosed in U.S. Pat. Nos. 3,732,111; 2,571,867; and 2,571,948. These methods require a relatively large volume of solvent in relation to the compounds of interest and result in a dilute extract which is limited in its application and which has few of the advantages of the concentrates which can be produced using volatile solvents.
U.S. Pat. No. 4,681,769 discloses a method for simultaneously extracting and concentrating in a series of high pressure countercurrent mechanical presses using relatively small amounts of vegetable oil as the solvent in an attempt to overcome the problem of dilution inherent in earlier processes. This method suffers from severe limitations in temperature and pressure ranges in an attempt to avoid unacceptable oxidative damage, color loss, yield losses, and flavor changes with the final result being that contact times must be unduly extended for up to 16-24 hours, adding greatly to the cost of the process. Extraction cycle times are unduly long for a given size pressing operation, and the process does not provide for a controlled degree of browning or for sterilization of the extract or of the residual solid. It is also limited to temperatures of less than 100.degree. F. Maximum pressures of up to about 500 PSI (cone pressure) are claimed and this severely limits the efficiency and throughput rate for a given size pressing operation, as shown by the disclosure of this patent.
U.S. Pat. Nos. 4,790,995 and 4,910,027 require the addition of a coating of animal protein to protect the spice from the loss of volatile aroma compounds during the sterilization process with water vapor. U.S. Pat. No. 4,210,678 requires bringing the moisture of the spice to above 8-14%, in some cases up to 16-20%, and holding the spice for an extended period of time prior to sterilization to equilibrate the moisture. This additional step is costly and time consuming.
Above all, there is the unsolved problem of obtaining satisfactory yields, quality, and throughput rates of acceptable extract and spice and herb solids having an acceptable content of active principle without undesirable oxidative damage to, and reduced stability of, the principal compounds of interest, while at the same time providing for simultaneous sterilization of both the spice or herb solid and extract.
Sesame oil is known to possess a unique combination of antioxidants including gamma-tocopherol, sesamol and its precursors and/or reaction products such as sesamolin and sesamolinol, and sterols with an ethylidiene side chain, such as delta-5 avenasterol and citrostadienol as described in EP 0,477,825 A2. As such, and as claimed in EP 0,477,825 A2, it is useful as a stabilizing agent in other vegetable oils. However, it is disclosed in the aforementioned patent that "cold pressed" sesame oil is not as stable as solvent-extracted sesame oil and therefore is not acceptable for the intended use.
EP 0,477,825 A2 states that sesame oil extracted by "cold pressing" is not sufficiently resistant to oxidative deterioration and "is found not to be effective in the present invention; in a typical instance it was found to have a Rancimat value of only 3.4 hours." as compared to an RBD sesame oil with "a Rancimat value of 30.7 hours." This would severely limit the utility of a prior art pressed oil but not one which has the economic advantage of being produced in the present process wherein no non-edible solvents are used and the residual press cake solids have significant economic importance as they contain a portion of the principal components of interest at standardized levels and have not been adulterated or contacted by any non-food grade substance.
Obviously, existing prior art procedures leave much to be desired, and it is a primary objective of the present invention to provide a procedure for the production of spice and herb products which have significantly reduced microbial counts in both the extract and residual solids without the use of undesirable chemicals, irradiation, or high moisture contents with the attendant uncontrolled browning and loss of volatiles. It is also an objective of this invention to produce a spice or herb solid that will rapidly and efficiently release standardized amounts of the principal components of interest into the food or beverage in which it is used. It is also a primary objective of the present invention to provide a procedure for the production of spice and herb products having enhanced stability and which otherwise obviates the shortcomings of the prior art.